ABSTRACT In the United States, 29.1 million persons live with type 2 diabetes mellitus (T2DM) and 49 million persons are food-insecure, both disproportionately impacting low-income communities. Food insecurity is strongly associated with the development of T2DM and, among people with T2DM, poor glycemic control, operating through nutritional, mental health, and behavioral pathways. Existing nutrition safety-net resources are inadequate to address the health effects of food insecurity. Policy makers increasingly recognize the premise that ?Food is Medicine? - i.e. that medically tailored food support for chronically ill, food-insecure people can play a critical role in achieving optimal health outcomes. In collaboration with Project Open Hand, a large non-profit nutrition agency that provides medically tailored meals and groceries to low-income, chronically ill residents of the San Francisco Bay Area, we propose a randomized controlled trial (RCT) of Changing Health through Food Support for Diabetes (CHEFS-DM). CHEFS-DM is a six-month intervention providing a DM-tailored diet meeting approximately 75% of daily energy requirements and designed based on American Diabetes Association guidelines, together with DM nutritional education provided by registered dieticians. In our pilot study, the intervention was feasible, acceptable, and associated with improvements in food security, diet quality, health behaviors, mental health, and trends towards improvements in acute care use and DM control. In this pragmatic RCT, we propose to rigorously evaluate the intervention among 400 low-income adults with T2DM recruited from networks of safety net clinics in San Francisco and Alameda counties, California. Leveraging POH's real-world programs, we will randomize participants 1:1 to intervention and control arms, following all participants with surveys, blood pressure measures, anthropometry, 24-hour recalls, medical record review and fasting blood draws at baseline and six months to assess intervention impacts on health outcomes; intervention participants will complete an additional twelve-month assessment to assess sustainability. In Aim 1, we will determine the impact of CHEFS-DM on diabetes health, hypothesizing the intervention will improve hemoglobin A1c (primary outcome) and other cardiometabolic outcomes [decreased fasting glucose, blood pressure (BP), lipids, acute care utilization, DM medication intensification and increased health-related quality of life (HRQoL)] (secondary outcomes). In Aim 2, we will use our published conceptual framework to understand the nutritional, mental, and behavioral paths through which CHEFS-DM may impact T2DM health outcomes. Finally, in Aim 3, we will determine the cost- effectiveness and sustainability of CHEFS-DM, and conduct a mixed-methods process evaluation to understand intervention strengths and limitations to inform scale-up. We hypothesize that the intervention may be cost- effective and possibly even cost saving, and that health benefits will be sustained after the intervention period. Our ultimate goal is to help stop the cycle of food insecurity and diabetes-related morbidity and mortality, consistent with the nutritional, DM-related and health disparities goals of US Healthy People 2020.